package com.magicalcoder.youyamvc.core.common.utils.safe;
import java.io.*;
/**
 * Created by www.magicalcoder.com on 14-4-3.
 * 799374340@qq.com
 */
    // Copyright (C) 1999-2002 by Jason Hunter <jhunter_AT_acm_DOT_org>.
// All rights reserved.  Use of this class is limited.
// Please see the LICENSE for more information.
    /***
     * A class to encode Base64 streams and strings.
     * See RFC 1521 section 5.2 for details of the Base64 algorithm.
     * <p>
     * This class can be used for encoding strings:
     * <blockquote><pre>
     * String unencoded = "webmaster:try2gueSS";
     * String encoded = Base64Encoder.encode(unencoded);
     * </pre></blockquote>
     * or for encoding streams:
     * <blockquote><pre>
     * OutputStream out = new Base64Encoder(System.out);
     * </pre></blockquote>
     *
     * @author <b>Jason Hunter</b>, Copyright &#169; 2000
     * @version 1.2, 2002/11/01, added encode(byte[]) method to better handle
     *                           binary data (thanks to Sean Graham)
     * @version 1.1, 2000/11/17, fixed bug with sign bit for char values
     * @version 1.0, 2000/06/11
     */
    public class Base64Encoder extends FilterOutputStream {

        private static final char[] chars = {
                'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
                'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
                'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd',
                'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
                'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
                'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7',
                '8', '9', '+', '/'
        };

        private int charCount;
        private int carryOver;

        /***
         * Constructs a new Base64 encoder that writes output to the given
         * OutputStream.
         *
         * @param out the output stream
         */
        public Base64Encoder(OutputStream out) {
            super(out);
        }

        /***
         * Writes the given byte to the output stream in an encoded form.
         *
         * @exception java.io.IOException if an I/O error occurs
         */
        public void write(int b) throws IOException {
            // Take 24-bits from three octets, translate into four encoded chars
            // Break lines at 76 chars
            // If necessary, pad with 0 bits on the right at the end
            // Use = signs as padding at the end to ensure encodedLength % 4 == 0

            // Remove the sign bit,
            // thanks to Christian Schweingruber <chrigu@lorraine.ch>
            if (b < 0) {
                b += 256;
            }

            // First byte use first six bits, save last two bits
            if (charCount % 3 == 0) {
                int lookup = b >> 2;
                carryOver = b & 3;        // last two bits
                out.write(chars[lookup]);
            }
            // Second byte use previous two bits and first four new bits,
            // save last four bits
            else if (charCount % 3 == 1) {
                int lookup = ((carryOver << 4) + (b >> 4)) & 63;
                carryOver = b & 15;       // last four bits
                out.write(chars[lookup]);
            }
            // Third byte use previous four bits and first two new bits,
            // then use last six new bits
            else if (charCount % 3 == 2) {
                int lookup = ((carryOver << 2) + (b >> 6)) & 63;
                out.write(chars[lookup]);
                lookup = b & 63;          // last six bits
                out.write(chars[lookup]);
                carryOver = 0;
            }
            charCount++;

            // Add newline every 76 output chars (that's 57 input chars)
            if (charCount % 57 == 0) {
                out.write('\n');
            }
        }

        /***
         * Writes the given byte array to the output stream in an
         * encoded form.
         *
         * @param buf the data to be written
         * @param off the start offset of the data
         * @param len the length of the data
         * @exception java.io.IOException if an I/O error occurs
         */
        public void write(byte[] buf, int off, int len) throws IOException {
            // This could of course be optimized
            for (int i = 0; i < len; i++) {
                write(buf[off + i]);
            }
        }

        /***
         * Closes the stream, this MUST be called to ensure proper padding is
         * written to the end of the output stream.
         *
         * @exception java.io.IOException if an I/O error occurs
         */
        public void close() throws IOException {
            // Handle leftover bytes
            if (charCount % 3 == 1) {  // one leftover
                int lookup = (carryOver << 4) & 63;
                out.write(chars[lookup]);
                out.write('=');
                out.write('=');
            }
            else if (charCount % 3 == 2) {  // two leftovers
                int lookup = (carryOver << 2) & 63;
                out.write(chars[lookup]);
                out.write('=');
            }
            super.close();
        }

        /***
         * Returns the encoded form of the given unencoded string.  The encoder
         * uses the ISO-8859-1 (Latin-1) encoding to convert the string to bytes.
         * For greater control over the encoding, encode the string to bytes
         * yourself and use encode(byte[]).
         *
         * @param unencoded the string to encode
         * @return the encoded form of the unencoded string
         */
        public static String encode(String unencoded) {
            byte[] bytes = null;
            try {
                bytes = unencoded.getBytes("8859_1");
            }
            catch (UnsupportedEncodingException ignored) { }
            return encode(bytes);
        }

        /***
         * Returns the encoded form of the given unencoded string.
         *
         * @param bytes the bytes to encode
         * @return the encoded form of the unencoded string
         */
        public static String encode(byte[] bytes) {
            ByteArrayOutputStream out =
                    new ByteArrayOutputStream((int) (bytes.length * 1.37));
            Base64Encoder encodedOut = new Base64Encoder(out);

            try {
                encodedOut.write(bytes);
                encodedOut.close();

                return out.toString("8859_1");
            }
            catch (IOException ignored) { return null; }
        }

        public static void main(String[] args) throws Exception {
            if (args.length != 1) {
                System.err.println(
                        "Usage: java com.oreilly.servlet.Base64Encoder fileToEncode");
                return;
            }

            Base64Encoder encoder = null;
            BufferedInputStream in = null;
            try {
                encoder = new Base64Encoder(System.out);
                in = new BufferedInputStream(new FileInputStream(args[0]));

                byte[] buf = new byte[4 * 1024];  // 4K buffer
                int bytesRead;
                while ((bytesRead = in.read(buf)) != -1) {
                    encoder.write(buf, 0, bytesRead);
                }
            }
            finally {
                if (in != null) in.close();
                if (encoder != null) encoder.close();
            }
        }
    }
